When you have the air vents down, cut out two of the louvers. I did one on each end. Then pop the vent back in and feel the difference between it an unmodified vent. Big difference in air flow. Those louvers real cut down the speed and volume. I modified all of ours.
If you're sitting in place for more than a few days, I also made solar sun shades for the windows. Massive difference in the internal temperature. Folks have been making these for years, but when I was reading up on them a lot of the images were missing or info was outdated, so I documented my build. Here's a write up I did:
https://www.wanderandreflect.com/202...creens-for-rv/